Bug 1074327

Summary: Upstream libvirt (from git) no longer supports host-passthrough, says "CPU specification not supported by hypervisor"
Product: [Community] Virtualization Tools Reporter: Richard W.M. Jones <rjones>
Component: libvirtAssignee: Libvirt Maintainers <libvirt-maint>
Status: CLOSED NEXTRELEASE QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: acathrow, jdenemar, rjones
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2014-03-12 15:42:26 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 910269    

Description Richard W.M. Jones 2014-03-09 20:17:18 UTC 
Description of problem:

Upstream libvirt (git ea1eadd6a31 from today) no longer seems to
work with cpu host-passthrough.  When running libguestfs-test-tool
(or any other libguestfs using program), it says:

  Original error from libvirt: unsupported configuration: CPU specification not supported by hypervisor [code=67 domain=10]

Version-Release number of selected component (if applicable):

libvirt from git
libguestfs 1.25.43
qemu-1.7.0-5.fc21.x86_64

How reproducible:

100%

Steps to Reproduce:
1. Compile libvirt from git.
2. Run this command:

  /path/to/libvirt/run libguestfs-test-tool

Additional information:

The libvirt XML that libguestfs generates is this:

<?xml version="1.0"?>
<domain type="kvm" xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
  <name>guestfs-4g8uz7ybjc5p4wu2</name>
  <memory unit="MiB">500</memory>
  <currentMemory unit="MiB">500</currentMemory>
  <cpu mode="host-passthrough">
    <model fallback="allow"/>
  </cpu>
  <vcpu>1</vcpu>
  <clock offset="utc">
    <timer name="rtc" tickpolicy="catchup"/>
    <timer name="pit" tickpolicy="delay"/>
    <timer name="hpet" present="no"/>
  </clock>
  <os>
    <type>hvm</type>
    <kernel>/var/tmp/.guestfs-1000/appliance.d/kernel</kernel>
    <initrd>/var/tmp/.guestfs-1000/appliance.d/initrd</initrd>
    <cmdline>panic=1 console=ttyS0 udevtimeout=600 no_timer_check acpi=off printk.time=1 cgroup_disable=memory root=/dev/sdb selinux=0 guestfs_verbose=1 TERM=xterm-256color</cmdline>
  </os>
  <on_reboot>destroy</on_reboot>
  <devices>
    <controller type="scsi" index="0" model="virtio-scsi"/>
    <disk device="disk" type="file">
      <source file="/tmp/libguestfs0yo7yP/scratch.1"/>
      <target dev="sda" bus="scsi"/>
      <driver name="qemu" type="raw" cache="unsafe"/>
      <address type="drive" controller="0" bus="0" target="0" unit="0"/>
    </disk>
    <disk type="file" device="disk">
      <source file="/tmp/libguestfs0yo7yP/overlay2"/>
      <target dev="sdb" bus="scsi"/>
      <driver name="qemu" type="qcow2" cache="unsafe"/>
      <address type="drive" controller="0" bus="0" target="1" unit="0"/>
      <shareable/>
    </disk>
    <serial type="unix">
      <source mode="connect" path="/tmp/libguestfs0yo7yP/console.sock"/>
      <target port="0"/>
    </serial>
    <channel type="unix">
      <source mode="connect" path="/tmp/libguestfs0yo7yP/guestfsd.sock"/>
      <target type="virtio" name="org.libguestfs.channel.0"/>
    </channel>
  </devices>
  <qemu:commandline>
    <qemu:env name="TMPDIR" value="/var/tmp"/>
  </qemu:commandline>
</domain>

Libvirt capabilities:

<capabilities>

  <host>
    <uuid>764d0cdd-007b-4fb4-a0e0-656db4931b03</uuid>
    <cpu>
      <arch>x86_64</arch>
      <topology sockets='1' cores='2' threads='2'/>
    </cpu>
    <power_management>
      <suspend_mem/>
      <suspend_disk/>
      <suspend_hybrid/>
    </power_management>
    <migration_features>
      <live/>
      <uri_transports>
        <uri_transport>tcp</uri_transport>
      </uri_transports>
    </migration_features>
    <topology>
      <cells num='1'>
        <cell id='0'>
          <memory unit='KiB'>16127992</memory>
          <cpus num='4'>
            <cpu id='0' socket_id='0' core_id='0' siblings='0-1'/>
            <cpu id='1' socket_id='0' core_id='0' siblings='0-1'/>
            <cpu id='2' socket_id='0' core_id='1' siblings='2-3'/>
            <cpu id='3' socket_id='0' core_id='1' siblings='2-3'/>
          </cpus>
        </cell>
      </cells>
    </topology>
    <secmodel>
      <model>selinux</model>
      <doi>0</doi>
      <baselabel type='kvm'>system_u:system_r:svirt_t:s0</baselabel>
      <baselabel type='qemu'>system_u:system_r:svirt_tcg_t:s0</baselabel>
    </secmodel>
  </host>

  <guest>
    <os_type>hvm</os_type>
    <arch name='alpha'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-alpha</emulator>
      <machine maxCpus='4'>clipper</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='armv7l'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-arm</emulator>
      <machine maxCpus='1'>integratorcp</machine>
      <machine maxCpus='1'>z2</machine>
      <machine maxCpus='1'>xilinx-zynq-a9</machine>
      <machine maxCpus='4'>vexpress-a15</machine>
      <machine maxCpus='4'>vexpress-a9</machine>
      <machine maxCpus='1'>versatileab</machine>
      <machine maxCpus='1'>versatilepb</machine>
      <machine maxCpus='1'>tosa</machine>
      <machine maxCpus='1'>lm3s6965evb</machine>
      <machine maxCpus='1'>lm3s811evb</machine>
      <machine maxCpus='1'>terrier</machine>
      <machine maxCpus='1'>borzoi</machine>
      <machine maxCpus='1'>spitz</machine>
      <machine maxCpus='1'>akita</machine>
      <machine maxCpus='4'>realview-pbx-a9</machine>
      <machine maxCpus='1'>realview-pb-a8</machine>
      <machine maxCpus='4'>realview-eb-mpcore</machine>
      <machine maxCpus='1'>realview-eb</machine>
      <machine maxCpus='1'>cheetah</machine>
      <machine maxCpus='1'>sx1-v1</machine>
      <machine maxCpus='1'>sx1</machine>
      <machine maxCpus='1'>n810</machine>
      <machine maxCpus='1'>n800</machine>
      <machine maxCpus='1'>musicpal</machine>
      <machine maxCpus='1'>mainstone</machine>
      <machine maxCpus='1'>kzm</machine>
      <machine maxCpus='4'>midway</machine>
      <machine maxCpus='4'>highbank</machine>
      <machine maxCpus='1'>verdex</machine>
      <machine maxCpus='1'>connex</machine>
      <machine maxCpus='2'>smdkc210</machine>
      <machine maxCpus='2'>nuri</machine>
      <machine maxCpus='1'>collie</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='cris'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-cris</emulator>
      <machine maxCpus='1'>axis-dev88</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='i686'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-i386</emulator>
      <machine canonical='pc-i440fx-1.7' maxCpus='255'>pc</machine>
      <machine maxCpus='255'>pc-q35-1.4</machine>
      <machine maxCpus='255'>pc-q35-1.5</machine>
      <machine maxCpus='255'>pc-q35-1.6</machine>
      <machine canonical='pc-q35-1.7' maxCpus='255'>q35</machine>
      <machine maxCpus='1'>isapc</machine>
      <machine maxCpus='255'>pc-0.10</machine>
      <machine maxCpus='255'>pc-0.11</machine>
      <machine maxCpus='255'>pc-0.12</machine>
      <machine maxCpus='255'>pc-0.13</machine>
      <machine maxCpus='255'>pc-0.14</machine>
      <machine maxCpus='255'>pc-0.15</machine>
      <machine maxCpus='255'>pc-1.0</machine>
      <machine maxCpus='255'>pc-1.1</machine>
      <machine maxCpus='255'>pc-1.2</machine>
      <machine maxCpus='255'>pc-1.3</machine>
      <machine maxCpus='255'>pc-i440fx-1.4</machine>
      <machine maxCpus='255'>pc-i440fx-1.5</machine>
      <machine maxCpus='255'>pc-i440fx-1.6</machine>
      <domain type='qemu'>
      </domain>
      <domain type='kvm'>
        <emulator>/usr/bin/qemu-kvm</emulator>
        <machine canonical='pc-i440fx-1.7' maxCpus='255'>pc</machine>
        <machine maxCpus='255'>pc-q35-1.4</machine>
        <machine maxCpus='255'>pc-q35-1.5</machine>
        <machine maxCpus='255'>pc-q35-1.6</machine>
        <machine canonical='pc-q35-1.7' maxCpus='255'>q35</machine>
        <machine maxCpus='1'>isapc</machine>
        <machine maxCpus='255'>pc-0.10</machine>
        <machine maxCpus='255'>pc-0.11</machine>
        <machine maxCpus='255'>pc-0.12</machine>
        <machine maxCpus='255'>pc-0.13</machine>
        <machine maxCpus='255'>pc-0.14</machine>
        <machine maxCpus='255'>pc-0.15</machine>
        <machine maxCpus='255'>pc-1.0</machine>
        <machine maxCpus='255'>pc-1.1</machine>
        <machine maxCpus='255'>pc-1.2</machine>
        <machine maxCpus='255'>pc-1.3</machine>
        <machine maxCpus='255'>pc-i440fx-1.4</machine>
        <machine maxCpus='255'>pc-i440fx-1.5</machine>
        <machine maxCpus='255'>pc-i440fx-1.6</machine>
      </domain>
    </arch>
    <features>
      <deviceboot/>
      <acpi default='on' toggle='yes'/>
      <apic default='on' toggle='no'/>
      <pae/>
      <nonpae/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='lm32'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-lm32</emulator>
      <machine maxCpus='1'>lm32-evr</machine>
      <machine maxCpus='1'>milkymist</machine>
      <machine maxCpus='1'>lm32-uclinux</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='m68k'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-m68k</emulator>
      <machine maxCpus='1'>mcf5208evb</machine>
      <machine maxCpus='1'>dummy</machine>
      <machine maxCpus='1'>an5206</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='microblaze'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-microblaze</emulator>
      <machine maxCpus='1'>petalogix-s3adsp1800</machine>
      <machine maxCpus='1'>petalogix-ml605</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='microblazeel'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-microblazeel</emulator>
      <machine maxCpus='1'>petalogix-s3adsp1800</machine>
      <machine maxCpus='1'>petalogix-ml605</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='mips'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-mips</emulator>
      <machine maxCpus='16'>malta</machine>
      <machine maxCpus='1'>mips</machine>
      <machine maxCpus='1'>mipssim</machine>
      <machine maxCpus='1'>pica61</machine>
      <machine maxCpus='1'>magnum</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='mipsel'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-mipsel</emulator>
      <machine maxCpus='16'>malta</machine>
      <machine maxCpus='1'>mips</machine>
      <machine maxCpus='1'>mipssim</machine>
      <machine maxCpus='1'>pica61</machine>
      <machine maxCpus='1'>magnum</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='mips64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-mips64</emulator>
      <machine maxCpus='16'>malta</machine>
      <machine maxCpus='1'>mips</machine>
      <machine maxCpus='1'>mipssim</machine>
      <machine maxCpus='1'>pica61</machine>
      <machine maxCpus='1'>magnum</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='mips64el'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-mips64el</emulator>
      <machine maxCpus='16'>malta</machine>
      <machine maxCpus='1'>mips</machine>
      <machine maxCpus='1'>mipssim</machine>
      <machine maxCpus='1'>pica61</machine>
      <machine maxCpus='1'>magnum</machine>
      <machine maxCpus='1'>fulong2e</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='ppc'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-ppc</emulator>
      <machine maxCpus='1'>g3beige</machine>
      <machine maxCpus='1'>virtex-ml507</machine>
      <machine maxCpus='1'>prep</machine>
      <machine maxCpus='1'>bamboo</machine>
      <machine maxCpus='1'>taihu</machine>
      <machine maxCpus='1'>ref405ep</machine>
      <machine maxCpus='15'>mpc8544ds</machine>
      <machine maxCpus='1'>mac99</machine>
      <machine maxCpus='32'>ppce500</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='ppc64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-ppc64</emulator>
      <machine maxCpus='256'>pseries</machine>
      <machine maxCpus='1'>virtex-ml507</machine>
      <machine maxCpus='1'>prep</machine>
      <machine maxCpus='1'>bamboo</machine>
      <machine maxCpus='1'>taihu</machine>
      <machine maxCpus='1'>ref405ep</machine>
      <machine maxCpus='15'>mpc8544ds</machine>
      <machine maxCpus='1'>g3beige</machine>
      <machine maxCpus='1'>mac99</machine>
      <machine maxCpus='32'>ppce500</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='ppcemb'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-ppcemb</emulator>
      <machine maxCpus='1'>g3beige</machine>
      <machine maxCpus='1'>virtex-ml507</machine>
      <machine maxCpus='1'>prep</machine>
      <machine maxCpus='1'>bamboo</machine>
      <machine maxCpus='1'>taihu</machine>
      <machine maxCpus='1'>ref405ep</machine>
      <machine maxCpus='15'>mpc8544ds</machine>
      <machine maxCpus='1'>mac99</machine>
      <machine maxCpus='32'>ppce500</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='s390x'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-s390x</emulator>
      <machine canonical='s390-virtio' maxCpus='255'>s390</machine>
      <machine canonical='s390-ccw-virtio' maxCpus='255'>s390-ccw</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='sh4'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-sh4</emulator>
      <machine maxCpus='1'>shix</machine>
      <machine maxCpus='1'>r2d</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='sh4eb'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-sh4eb</emulator>
      <machine maxCpus='1'>shix</machine>
      <machine maxCpus='1'>r2d</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='sparc'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-sparc</emulator>
      <machine maxCpus='1'>SS-5</machine>
      <machine maxCpus='1'>SPARCbook</machine>
      <machine maxCpus='1'>SPARCClassic</machine>
      <machine maxCpus='1'>SS-4</machine>
      <machine maxCpus='1'>LX</machine>
      <machine maxCpus='1'>Voyager</machine>
      <machine maxCpus='4'>SS-20</machine>
      <machine maxCpus='4'>SS-600MP</machine>
      <machine maxCpus='4'>SS-10</machine>
      <machine maxCpus='1'>leon3_generic</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='sparc64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-sparc64</emulator>
      <machine maxCpus='1'>sun4u</machine>
      <machine maxCpus='1'>Niagara</machine>
      <machine maxCpus='1'>sun4v</machine>
      <domain type='qemu'>
      </domain>
    </arch>
    <features>
      <deviceboot/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='unicore32'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-unicore32</emulator>
      <machine maxCpus='1'>puv3</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='x86_64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-x86_64</emulator>
      <machine canonical='pc-i440fx-1.7' maxCpus='255'>pc</machine>
      <machine maxCpus='255'>pc-q35-1.4</machine>
      <machine maxCpus='255'>pc-q35-1.5</machine>
      <machine maxCpus='255'>pc-q35-1.6</machine>
      <machine canonical='pc-q35-1.7' maxCpus='255'>q35</machine>
      <machine maxCpus='1'>isapc</machine>
      <machine maxCpus='255'>pc-0.10</machine>
      <machine maxCpus='255'>pc-0.11</machine>
      <machine maxCpus='255'>pc-0.12</machine>
      <machine maxCpus='255'>pc-0.13</machine>
      <machine maxCpus='255'>pc-0.14</machine>
      <machine maxCpus='255'>pc-0.15</machine>
      <machine maxCpus='255'>pc-1.0</machine>
      <machine maxCpus='255'>pc-1.1</machine>
      <machine maxCpus='255'>pc-1.2</machine>
      <machine maxCpus='255'>pc-1.3</machine>
      <machine maxCpus='255'>pc-i440fx-1.4</machine>
      <machine maxCpus='255'>pc-i440fx-1.5</machine>
      <machine maxCpus='255'>pc-i440fx-1.6</machine>
      <domain type='qemu'>
      </domain>
      <domain type='kvm'>
        <emulator>/usr/bin/qemu-kvm</emulator>
        <machine canonical='pc-i440fx-1.7' maxCpus='255'>pc</machine>
        <machine maxCpus='255'>pc-q35-1.4</machine>
        <machine maxCpus='255'>pc-q35-1.5</machine>
        <machine maxCpus='255'>pc-q35-1.6</machine>
        <machine canonical='pc-q35-1.7' maxCpus='255'>q35</machine>
        <machine maxCpus='1'>isapc</machine>
        <machine maxCpus='255'>pc-0.10</machine>
        <machine maxCpus='255'>pc-0.11</machine>
        <machine maxCpus='255'>pc-0.12</machine>
        <machine maxCpus='255'>pc-0.13</machine>
        <machine maxCpus='255'>pc-0.14</machine>
        <machine maxCpus='255'>pc-0.15</machine>
        <machine maxCpus='255'>pc-1.0</machine>
        <machine maxCpus='255'>pc-1.1</machine>
        <machine maxCpus='255'>pc-1.2</machine>
        <machine maxCpus='255'>pc-1.3</machine>
        <machine maxCpus='255'>pc-i440fx-1.4</machine>
        <machine maxCpus='255'>pc-i440fx-1.5</machine>
        <machine maxCpus='255'>pc-i440fx-1.6</machine>
      </domain>
    </arch>
    <features>
      <deviceboot/>
      <acpi default='on' toggle='yes'/>
      <apic default='on' toggle='no'/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='xtensa'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-xtensa</emulator>
      <machine maxCpus='4'>sim</machine>
      <machine maxCpus='4'>lx200</machine>
      <machine maxCpus='4'>lx60</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='xtensaeb'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-xtensaeb</emulator>
      <machine maxCpus='4'>sim</machine>
      <machine maxCpus='4'>lx200</machine>
      <machine maxCpus='4'>lx60</machine>
      <domain type='qemu'>
      </domain>
    </arch>
  </guest>

</capabilities>

Additional request:

Please run libvirt against latest libguestfs-test-tool to ensure
it doesn't regress.
Comment 1 Jiri Denemark 2014-03-10 10:49:56 UTC 
Rich, I don't think there is a regression here. Capabilities XML shows

    <cpu>
      <arch>x86_64</arch>
      <topology sockets='1' cores='2' threads='2'/>
    </cpu>

which means libvirt was not able to detect host CPU model. If you think there should be no reason for this when you are asking for host-passthrough model, you're definitely correct but libvirt currently requires it and always has. We should fix it though. Anyway, the question is why libvirt did not find any CPU model on your host. Since you're running libvirt from git, I suspect this is because libvirtd was not able to find cpu_map.xml. Do you also have libvirt installed on the host? In other words, does /usr/share/libvirt/cpu_map.xml exist? If not, we found the reason for the failure described in this bug.
Comment 2 Richard W.M. Jones 2014-03-10 11:55:20 UTC 
So it turns out that using:

  ./configure --prefix=/usr

fixes it.

However:

(1) The error message should say that it cannot load cpu_map.xml.

(2) This is using the system libvirt cpu_map.xml, which works in
this case, but wouldn't work in other cases.  The ./run script
should be able to set an environment variable so libvirt picks
the cpu_map.xml from its source tree.
Comment 3 Jiri Denemark 2014-03-10 15:28:54 UTC 
Patch proposed upstream: https://www.redhat.com/archives/libvir-list/2014-March/msg00621.html
Comment 4 Jiri Denemark 2014-03-12 15:42:26 UTC 
This is now fixed in git by v1.2.2-100-ge562e82:

commit e562e82f76614beff132ab48d3f0dabf64b20c5b
Author: Jiri Denemark <jdenemar>
Date:   Mon Mar 10 16:00:49 2014 +0100

    Load CPU map from builddir when run uninstalled
    
    When libvirtd is run from a build directory without being installed, it
    should not depend on files from a libvirt package installed in the
    system. Not only because there may not be any libvirt installed at all.
    We already do a good job for plugins but cpu_map.xml was still loaded
    from the system.
    
    The Makefile.am change is necessary to make this all work from VPATH
    builds since libvirtd has no idea where to find libvirt sources. It only
    knows the path from which it was started, i.e, a builddir.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1074327
    Signed-off-by: Jiri Denemark <jdenemar>